I have seen the primary seep gas when the float level is to high. Hopeflly you are adjusting the float level correctly. I have always removed the sight glass / brass plug. Cranked the engine and watch the fuel level. I always set mine a little blow the sight hole, then I press on the fender and some gas should trickle out. Adjust the fuel regulator to about 6 - 7 psi, then with a screwdriver and 5/8 wrench turn the float adjustment to achieve this setting, while loosen the top then turning the wrench. Adjust down for less gas and adjust up for more gas. You will need to keep the top snug while turning but not to tight. Hope this makes since.
If the float level is set correctly and it contiunes to leak gas, then the needle seat is not sealing. Could be trash or bad needle seat.
Hope this is some help.
John